An OLED (organic light-emitting diode) is a light-emitting diode (LED), in which the emissive electroluminescent layer is a film of an organic compound, which emits light in response to an electric current. A typical OLED has a multi-layer structure, and typically includes an indium tin oxide (ITO) anode, and a metal cathode. Sandwiched between the ITO anode and the metal cathode are several organic layers, such as a hole injection layer (HIL), a hole transfer layer (HTL), an emitting material layer (EML), an electron transfer layer (ETL), and an electron injection layer (EIL).
Conventional OLED devices use emissive materials based on expensive iridium phosphorescent complexes or inefficient fluorescent based organic small molecules. The art recognizes the on-going need for new emissive materials that are more economical and/or more efficient than conventional iridium-based emissive materials or fluorescent-based emissive materials. The art recognizes the need for such emissive materials for organic thermally activated delayed fluorescence (TADF) emitters in particular.